Alpha-numeric character display device and method, whose characters are formed of light emitting diodes

ABSTRACT

An alpha-numeric character display device and method of making the same. The alpha-numeric characters are formed of a plurality of light emitting diodes mounted on a transparent base plate with their respective P-N junctions lying in planes perpendicular to the base plate and arranged in a pattern to exhibit selectively a plurality of individual display units. Energization selectively of different diodes is accomplished through a novel conductive lead pattern laid down in layers above and over the surface of the base plate, the conductive leads being separated from each other by a novel insulating arrangement which is produced in a novel manner.

United States Patent i191 Usui [111 3,827,048 [4 July 30 1974ALPHA-NUMERIC CHARACTER DISPLAY DEVICE AND METHOD, WHOSE CHARACTERS AREFORMED OF LIGHT EMITTING DIODES Related US. Application Data [63]Continuation-impart of Ser. No. 320,720, Jan. 3,

Setsuo Usui, Kanagawa-ken, Japan [30] Foreign Application Priority DataAug. l0, i972 Japan 47-80110 [52] US. Cl. 340/366 R, 340/166 R [51] Int.Cl. 60% 5/00 [58] Field of Search 340/336 B, l66 R, 324 M; 3l3/l08 D,336 R [56] References Cited UNITED STATES PATENTS 3,388,292 6/l968 Burns340/324 M Primary Examinerl-larold l. Pitts Attorney, Agent, orFirml-lill, Gross, Simpson, Van Santen, Steadman, Chiara & Simpson 5 7ABSTRACT An alpha-numeric character display device and method of makingthe same. The alpha-numeric characters are formed of a plurality oflight emitting diodes mounted on a transparent base plate with theirrespective P-N junctions lying in planes perpendicular to the base plateand arranged in a pattern to exhibit selectively a plurality ofindividual display units. Energization selectively of different diodesis accomplished through a novel conductive lead pattern laid down inlayers above and over the surface of the base plate, the conductiveleads being separated from each other by a novel insulating arrangementwhich is produced in a novel manner.

12 Claims, 26 Drawing Figures PATENTED JUL30 I974 3,827, 048

SHEET 1 0F 8 PATENTED M 4 BM I. 048

sum 5 or a Fig. 18

PATENTEnJummu sum a or a ALPHA-NUMERIC CHARACTER DISPLAY DEVICE ANDMETHOD, WHOSE CHARACTERS ARE FORMED OF LIGHT EMITTING DIODES RELATEDAPPLICATIONS BACKGROUND OF THE INVENTION The underlying basic design ofan alpha-numeric character display device is now well known, as witnessthe advent of electronic calculators. A common form of such a device isan evacuated tube containing an ionizable gas, such as neon. Eachcharacter is made up of 7 cathode segments in the form of a figure 8. Aplurality of such characters are formed on a single tube and areselectively caused to glow to display the character desired.

Devices of the above type have had a disadvantage in that the amount oflight which can be emitted from a compact structure is relatively small.The depth of the display device is also a critical factor in theadaptation of the device for its intended use.

In my copending application, Ser. No. 320,720, I have disclosed analpha-numeric display device which employs light emitting diodes to formthe alphanumeric characters, the diodes having P-N junctions lying inplanes perpendicular to a transparent base plate on which they aremounted.

Light emitting diodes are known. The emitted light from such a diodecomes from hole-electron recombi-' nations. In a solid-statelight-emitting diode the supply of higher energy electrons is providedby forward biasing the diode, thus injecting electrons into the N region(and holes into the P region). The injected holes and electrons thenrecombine with the majority carriers near the junction. Therecombination radiation is then emitted in all directions.

Light emitting diodes have been used in alphanumeric character displaydevices, and one such structure is disclosed in Electronics, May 1 l,1970, pages 88 to 93.

In an alpha-numeric character display device of the present invention,the width of the light emitting diodes determines the width of the linesdefining the segments of the design. This enables an extremely fine linepattern to be obtained.

BRIEF SUMMARY OF THE INVENTION The present invention provides a novelmethod of mounting light emitting diodes on a transparent base plateforming the conductive leads to the different diodes, and a noveldisplay device structure.

In a first'preferred form of the present invention, a conductive wirepattern which corresponds to the contact terminals of the electronicparts, such as a light emitting diode or a transistor, is formed on afirst glass plate. Thereafter, a first insulating resin layer is formedon the conductive wire pattern layer. Predetermined parts of this resinlayer are removed in order to hold the electronic parts.

The electronic parts are inserted into etched recesses and then a photosensitive resin is coated on both the electronic parts and the firstresin layer so that the electronic parts are temporarily fixed to theconductive pattern layer. Thereafter, the electronic parts arecompletely fixed by a photo sensitive adhesive resin which is pouredbetween the electronic parts and the first glass plate and theconductive pattern layer.

After that, a second insulating resin is formed on the first insulatingresin layer through the photo sensitive resin layer which is utilized tofix temporarily the electronic parts. However, this second resin layeris removed in predetermined places, such as the connection point betweenthe contact terminal of the electronic parts and the conductive patternlayer, and also an outer lead terminal.

Then, a conductive resin is poured into the above mentioned connectionpoint and into the outer lead terminal.

Finally, a second glass plate having a reflective layer is adhered tothe second insulating layer, which reflective layer effectively reflectslight to the outside through the above photo sensitive adhesive resinand the first glass plate.

It is an object of the present invention to provide a novelalpha-numeric character display device employing a light-emitting diodefor each segment of the display.

It is a further object of the present invention to provide analpha-numeric character display device employing light-emitting diodeshaving a novel integrated circuit connecting the ohmic contacts of thevarious diodes.

It'is still another object of the present invention to provide a novelalpha-numeric character display device employing a fine line lightsource for each indicating line of the device.

It is another and further object of the present invention to provide anovel alpha-numeric character display device having a high degree ofbrightness.

A still further object of this invention is to provide a novelalpha-numeric character display device which is economical tomanufacture and which is rugged and reliable in use.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric diagrammaticview of a light emitting diode as employed in one preferred embodimentof the present invention;

FIG. 2 is a cross-sectional view of a conductive layer before formingthe lead pattern as employed in the present invention;

FIG. 3 is a plan view of the upper surface of a portion of thetransparent plate after forming the lead pattern thereon;

FIG. 4 is a cross-sectional view taken on line IVIV in FIG 3;

FIG. 5 is a plan view of the plate coated by the first insulating resinlayer over the conductive layer;

FIGS. 6 and 7 are a cross-sectional and a perspective view,respectively, corresponding to FIG. 5;

FIG. 8 and FIGS. 10 to 17 show in a sequence of diagrammatic sectionalviews the formation of an alphanumeric character display deviceembodying a preferred form of the present invention;

FIG. 9 shows a photo mask pattern employed in the manufacture of thedevice, which overlies the first insulating resin layer;

FIG. 18 is a fragmentary cross-sectional view of the commencement of theformation of a second preferred embodiment of the present invention andshows a substrate glass plate supported in spaced relation on a baseglass plate;

FIG. 19 is a view of the conductive pattern laid down on the glasssubstrate of FIG. 18;

FIG. 20 is an enlarged view of a portion of FIG. 19;

FIG. 21 is a view of a second pattern of insulating material coated onthe first conductive pattern, with pockets for receiving the diodes;

FIG. 22 shows the light emitting diodes of two character units mountedin place with a third conductive resin layer mounted on the secondlayer;

FIG. 23 is a fragmentary isometric view of a portion of FIG. 22;

FIG. 24 shows a conductive paint poured onto the third resin layer andinto the cavities;

FIG. 25 shows the upper portion of the conductive pattern having beenselectively blasted away; and

FIG. 26 shows the resulting product.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made tothe first preferred embodiment of the present invention.

In FIG. 1 of the drawings, there is shown therein a lightemitting diode1 having a P-N junction formed between a P-type region 2 and an N-typeregion 3. This diode is preferably made, for example, of galliumphosphide, silicon carbide or gallium nitride. The diode l is preferablymade by cutting a semiconductor wafer with a diamond saw. Ohmic contacts4 and 5 are formed on the P-type and N-type regions 2 and 3respectively.

By way of example, and not by way of limitation, it has been found thatthe following dimensions for the diode are particularly effective. Thethickness dimension a of the P-type region is preferably 50 to 100microns with 80 microns being particularlysuitable. The thicknessdimension b of the N-type region is preferably between 200 and 300microns with 250 microns being particularly suitable. The maximumthickness dimensions c and d of the ohmic contacts are preferably of theorder of 1,000 Angstroms. The length dimension e of the light emittingdiode is preferably approximately 2 millimeters. The width dimension fis preferably approximately 50 to 100 microns.

The ultimate product is a device which includes a number ofalpha-numeric character units mounted in a common plane which arearranged to be individually selectively energized. Each character unitis made up of nine diodes, seven of which are in a conventional figure 8pattern, while the two additional diodes are for a decimal point and adash. One electrode of all diodes of a single character unit areelectrically connected together through a first conductive lead. Theother electrode of each diode of a single unit is separately connectedto a different second conductive lead, there being nine secondconductive leads, one each diode of the character unit. Allcorrespondingly located diodes of each character unit are connectedtogether through their respective associated leads. The commonlyconnected electrodes of each character unit have a separate terminal foreach character unit. This will be more fully understood when the secondembodiment of the present invention is described in connection with FIG.19.

The method of making the first embodiment will now be described.Referring first to FIG. 2, a glass plate 6 is dipped in Cr So liquid for24 hours and then the glass plate 6 is washed with water and withacetone.

After that, as shown in FIG. 2, an aluminum layer 7 (approximately 2p.thick), an aluminum-copper alloy layer 8 (about 0.5 to 1.0 p.) and acopper layer 9 (about By.) are, in turn,.deposited on the glass plate 6by any well known vapor evaporation method. The thickness of all thedeposited metal layer is preferably more than 5p. so that, in the finalprocess of the manufacture of this device, the lead frame is connectedto the metal layer firmly by solder.

The AI-Cu alloy layer 8 and the relatively thick Al layer 7 helps toproduce the high resolution of the lead wire pattern on the glass plate6 during the etching process. Moreover, the relatively thick Al layer 7adheres more firmly to the glass layer 6 than would copper, andaccordingly, this avoids the so-called side etching.

This glass plate 6 with the metal layers is kept in the open air forabout 24 hours at 40C and then it is baked for about 2 hours at C inorder to cause better adherence. of the respective layers to each other.

In the next step, on the surface of the deposited layer 9, a photoresist is deposited by about 1p. thickness. Any suitable photo resistmay be used such as that available under the trademark AZ-l350I-I. Thisphoto resist is pre-baked for 30 minutes at 90C, and then is exposed byusing a mask which has a predetermined conductive pattern. This exposuretime is for about 2 to 3 minutes under thousand Iux.

The pattern etching may be done by the next few steps. At first, the Culayer 4 is completely etched in liquid composed of I-INO H O 1:1 (30 to35C) for 45 to 50 minutes. This etching speed is selected at B t/min.After washing the plate with water, the above resist layer is removed byacetone, for example. This etched copper pattern layer is utilized as anetching mask for the Al layer 8. The Al layer 8 is etched in a mixedliquid of NaOH (or KOI-I) H O 2001 for 5 to 10 minutes at 20C. Thisspeed is suitable at l t/min. The Al-Cu alloy layer 8 may be etchedduring the etching process of the Cu layer 9 and the Al layer 7simultaneously. After etching the above, the plate is washed by waterand acetone, and then dried.

Referring to FIG. 3, there is shown thereon a conductive pattern layer10 on the glass plate 6. The conductive pattern layer 10 comprises aplurality of segments 11 to 20 with the conductive pattern 20 providinga common electrode.

Light emitting diodes will be set in the gaps 21 to 29 located betweenthe segments 11 to 19 and the common conductive segment 20. As shown inFIG. 3, this display shape is a well known Figure 8 type with a decimal.point and a dash. The terminal tabs for the various conductive segmentsare indicated with the respective numeral of each tab coupled with aprime.

FIG. 4 shows a cross-sectional view taken on the line IIA'-IIA' in FIG.3 and shows the position of representative conductive segments 16 and 20on the glass substrate.

In the next step, a first insulating resin layer 30, which serves tohold the light emitting diode is formed on the glass plate 6 and theconductive layer 10 as shown in FIG. 6. In forming this first insulatingpattern 30, as shown in FIGS. 5, 6 and 7, the portion on which the lightemitting diode is held should be uncovered, and the outer conductiveconnection points 11 to 2.0 are also uncovered. It is very importantthat the conductive segments 11 to 20 be contacted with the lightemitting diode around the center portion thereof, because, effectively,the concave portion of the resin layer 30 serves to holdthe lightemitting diodes.

FIGS. 6 and 7 show a cross-sectional view and an isometric view takenalong the line VIVI of FIG. 5. A recess 31 will support the lightemitting diode. The above photo sensitive resin 30 available under thetrade name SONNE 1027 or SONNE X-l 11" may be colored by a dye such as ablue color, for example. This color density is selected so that theresin 30 becomes hard by a predetermined light strength and further theresin 30 serves as an optical isolator. The thickness of this resinlayer 30 should be the same thickness as the light emitting diode 1.

In the manufacture of the photo resin layer 30, this resin is poured onthe plate 6 which has the conductive pattern segments 10, and then theglass photo mask is contacted to the poured resin layer through thepolyester film (transparent). This polyester film may be firmlycontacted to the poured resin by alcohol. In order to make this photoresin layer 30, the exposure is done under approximately 100 thousandlux for 3 minutes. After the exposure, this plate is washed by using anultrasonic wave in N-Butyl alcohol. Thereafter, the plate is rinsed byethyl-ether and is dried.

Referring to FIG. 8, the light emitting diode 1 is mounted in the recess31 so that the P-N junction thereof is faced the glass plate 6. Thisstep of inserting the diode 1 in the recess 31 is easy and has highreliability since the recess 31 serves as a holder or supporter for thediode.

After mounting the diode 1, it is temporarily fixed by the next step.First of all, on whole surface of the plate 6 is coated with aphoto-sensitive resin available under the trade name SONNE KPM 1027 (atransparent material). Then, this resin is exposed by using the patternmask 32 which is composed of mask portions 33 and a non-mask portion 34.Accordingly, the only area which corresponds to the non-mask portion 34of the mask 32 becomes hard.

FIGS. 10 and 11 show a resin layer 35 which serves to fix the diode 1temporarily.

Thereafter, as shown in FIG. 12, a transparent photosensitive resin 36,(KPM 1027), is poured on the upper surface. By the evacuation of airunder the diode 1, the resin, KPM I027, penetrates between the glassplate 6 and the diode l.

The terminal tabs 11' through 19 are electrically connected to parallelextending conducting strips laid down in grooves in the locationsindicated as 11" through 19", respectively, in FIG. 9, the grooves forconducting strips 15" through 18" being shown in FIG. 11.

As shown in FIG. 12, a polyester film 37 is contacted with the resinlayer 36 so as to minimize some unwanted shapes after the exposure whichis done in the next step.

Moreover, a mask 38 which covers the lead connection points 11 to 2l' isformed on the back of the glass plate 6, as shown in FIG. 12. Therefore,since light beam 39 is radiated from the underside of the glass plate 6,only the part of the resin which is under the diode I is hardened.Namely, both the mask 38 and conductive pattern 10 provide mask effects.

As a result, the diode 1 is firmly fixed to the glass plate 6. As one ofthe merits of this invention, since this resin 39 is filled into the gap26, there is no concern that the conductive resin penetrates into thegap 26 during the next steps. In other words, each of the conductivelayers 20 are completely isolated from each other.

After removing the polyester film 37, a photo sensitive resin, such asKPM 1027 (a transparent material) is poured. This resin, after theevacuation of air, is exposed by using a photo mask similar to the mask32 shown in FIG. 9. This exposed resin is washed by using an ultrasonicwave and then the plate is exposed for 10 minutes.

Consequently, as shown in FIG. 13, this resin layer 40 uncovers only theconnection points between the conductive pattern 10 and the electrodes 4and 5, and also uncovers the outer lead connection point 16'.

After that, a conductive resin 41, such as AHOMEX- AG or EPOTEK H3 1'(trade name) for example, is coated on the plate by a brush and heatedat approximately to C for about 1 hour (FIG. 14).

The conductive resin layer 41 is selectively removed by sand-papering,as shown in FIG. 15. Thus, the electrodes 4 and 5 are electricallyconnected to the conductive layer 10 by the conductive resin 41, andmoreover, the conductive layer 10 is electrically connected to theconductive resin 41 in a recess 42 which is to be connected to outerleads (not shown).

As the final step, as shown in FIG. 16, a glass plate 43 having areflective layer 44 is adhered, and finally, it may be mounted on apredetermined lead frame. This reflective layer 44 effectively reflectsthe light produced by the diode l to the outside through the window 39and the glass plate 6.

It will be understood that when a predetermined voltage bias is suppliedacross the electrodes of the diode shown in FIG. 16 through theconductive leads l6 and 20, light is emitted from the P-N junction ofthe diode 1 Since the recess 31 is provided in the first resin layer 30,the diode 1 is easily inserted into its desired position and,accordingly, there is no misalignment of the diode Since the conductivepattern layer 10 is formed on nearly the whole area of the glass plate6, this pattern layer 10 serves as a photo mask to make the hard resinlayer 39 on which the diode 1 is fixed.

In order to fix the diode l, the photo mask 32 which is the same as themask to form the second resin layer 40 is commonly used in two stepsduring the manufacture.

Since the resin 39 for fixing the diode l is poured into the gap 26before coating of the conductive resin 41, any undesirable short circuitbetween the conductive layer 16 and 20 is avoided.

A modified form of the preferred embodiment of the present inventionwill now be described with reference being had to FIGS. 18 to 26.

It starts, as did the first embodiment, by laying down a conductivelayer on a glass plate 6. The conductive layer is preferably a compositelayer 7 of aluminum, a layer 8 of aluminum-copper alloy, and a layer 9of cop-' per. In the alternative it may be only a single layer of copper(see FIG. 18). The glass plate 6 is then secured in spaced relation to asupport plate 45 by tacks of glue 46.

The conductive layer, whether it is a composite layer or a single layer,will hereinafter be referred to'as conductive layer 9. This layer is nowetched to form the conductive pattern shown in FIG. 19. It will be notedthat there are eleven tabs or terminals 47 to 57 along the lower side,one for each alpha-numeric character unit. There are eleven tabs orterminals 58 to 68 along the upper side, only tabs 59 to 68 being used.

Each of the eleven character units shown in FIG. 19 is made up of ninediodes. The conductive pattern for the two character units located abovetabs 56 and 57 are shown as a fragmentary greatly enlarged view in FIG.20.

Let it be assumed that the anode electrodes of the diodes are to beselectively connected respectively to the tabs 47 to 57. The cathodeelectrodes of the diodes would then be selectively connected ashereinafter to be described to the tabs 59 to 67. When one of the tabs47 to 57 is connected to a potential source the anodes of all of thediodes in the one character unit associated with such a tab areenergized. What diodes radiate light, however, depends on which diodeshave their cathode electrodes connected to the negative side of thepotential source. Since there are nine diodes for each character unit,and hence nine cathodes, the cathodes of all similarly located diodesmay be connected to a common conductive lead, there being one lead foreach terminal tab 59 to 67. These conductive leads are located alongpaths 69 to 77 running parallel to the length of the device as indicatedby the dash-dot lines in FIG. 20. They lie in a plane, however, abovethe plane of the conductive pattern and separated therefrom by suitableinsulating material.

Referring to FIG. 20, but in a manner later to be brought out, thecathode electrode of each diode representing dash is connected to lead69. The cathode of each diode forming the middle horizontal bar of eachcharacter is connected to lead 70. The cathode of the diode of eachcharacter forming the top bar is connected to lead 71. The cathode ofthe diode of each character forming the top right hand vertical bar isconnected to lead 72. The cathode of each diode forming the top lefthand vertical bar is connected to lead 73'. The. cathode of each diodeforming the lower right hand vertical bar is connected to lead 74. Thecathode of each diode forming the lower left hand vertical bar isconnected to lead 75. The cathode of each diode forming the bottomhorizontal bar is connected to lead 76. The cathode of each diodeforming a decimal point is connected to lead 77.

It will be obvious from the above that it is necessary to separate theconnective leads 69 to 75 except at certain desired connection points.The manner in which this is done will now be described.

Over the conductive pattern of FIG. 19 there is deposited an insulatinglayer 78 with the portions thereof at which the light emitting diodesare to be supported removed and with the portion thereof at the outerlead terminals also removed. See FIG. 21. The insulating layer 78 hasnine windows 79 to 87 for each character through which connections willlater be made to subsequently form leads 69 to 77 respectively. Theportions of the layer 78 removed for receiving the diodes from pockets88 to 96 for each character, as shown in FIG. 21. The diodes are mountedin place in the pockets 88 to 96.

The next step is to form a third layer 97 of insulating material onlayer 78. The upper surface of this insulating layer is provided withgrooves along lines 69 to 77 (see FIG. 22). The conductive leads canthen be buried therein. The second insulating layer 97 provides a sea]at the edge of the pocket.

Now on the insulating layer 97 and on every diode a conductive paintlayer 98 is coated (FIG. 24). Thereafter, a portion of the thickness ofthe layer 98 is removed as shown in FIG. 25. This completes now theconnections between the conductive pattern layer and the conductiveleads.

The substrate glass 6 is now removed from the base support 45. The glassplate 6 is then cut and a lead frame having solder plated layer thereinis connected by heating.

It will be apparent to those skilled in the art that many modificationsand variations may be effected without departing from the spirit andscope of the novel concepts of the present invention.

I claim as my invention:

1. In an alpha-numeric character display device composed of a pluralityof similar display units, each having a plurality of light emittingdiodes similarly arranged in a display array to be selectively energizedto depict different desired characters, the combination comprising atransparent glass base plate, a conductive layer pattern formed on saidbase plate having individual paths for one side of each diode of eachdisplay unit and having a common path for the other side of all diodesin one display unit but separate paths for different units, a pluralityof parallel disposed conductive leads corresponding in number to thetotal number of diodes in a single display unit running lengthwise ofsaid device in a plane above said conductive pattern, the first side ofall similarly located diodes of the different display units beingelectrically connected together through said conductive leads and saidconductive layer pattern, there being one conductive lead for each groupof similarly located diodes, and a terminal for each conductive lead anda terminal for each common path to said other side of the diodes of eachdisplay unit.

2. An alpha-numeric character display unit comprising a transparentnon-conductive plate, a conductive layer on one surface of said plateshaped in a predetermined pattern, said pattern including separated segment portions spaced to form a seven arm figure 8 configuration withpairs of said segment portions on opposite sides of said arm locations,and separate segment portions forming the other side of the armlocations, the segment portions forming one side of each arm locationbeing commonly connected, a terminal for said commonly connected segmentportions, separate subterminals for each said other segment portion,separate lead conductors for the segments forming the other side of eacharm location respectively, first insulating layer means covering saidconductive layer except for pockets opposite said arm locations, a lightemitting diode in each pocket having anode and cathode electrodes havingtheir respective pn junctions in planes perpendicular to said plate,said electrodes being in abutting electrical contact respectively withsegment portions on each side of said arm locations, a second insulatinglayer covering said first insulating layer and said diodes, said secondinsulating layer having grooves in the upper surface thereof in whichsaid lead conductors are disposed, said insulating layers having windowstherethrough below each lead conductor opposite a different sub-terminalrespectively, a conductive material filling each of said windows andconnecting each of said lead conductors with its associatedsub-terminal, and a third insulating layer covering said secondinsulating layer.

3. An alpha-numeric character display unit, comprising a transparentnon-conductive plate, a conductive layer on one surface of said plateshaped in a predetermined pattern, said pattern including separatedsegment portions spaced to form a seven arm figure 8 configuration withpairs of said segment portions on opposite sides of said arm locations,the separate segment portions formingthe other side of the armlocations, the segment portions forming one side of each arm locationbeing commonly connected, a terminal for said commonly connected segmentportions, separate subterminals for each said segment portion, separatelead conductors for the segments forming the other side of each armlocation respectively, first insulating layer means covering saidconductive layerexcept for pockets opposite said arm location, a lightemitting diode in each pocket having anode and cathode electrodes havingtheir respective pn junctions in planes perpendicular to said plate,said electrodes being in abutting electrical contact respectively withsegment portions on each side of said arm locations, said leadconductors being disposed on the opposite surface of said firstinsulating layer means from said conductive layer, said first insulatinglayer means having a window therethrough below each lead conductoropposite a different subterminal respectively, a conductive materialfilling each of said windows and connecting each of said lead conductorswith its associated sub-terminal, and a second insulating layer coveringsaid first insulating layer.

4. An alpha-numeric character display unit according to claim 2, inwhich said second insulating layer is a transparent resin, and a portionof the resin forming said second layer lies between each diode junctionand said transparent nonconductive plate.

5. A combination according to claim 1, in which a transparent resinlayer lies between each diode and said transparent glass plate, saidresin layer forming a contiguous layer with said conductive layerpattern below each of said diodes.

6. A combination according to claim 1, in which an insulating resinlayer is formed on said conductive pattern layer and a second insulatingresin layer is formed on said first insulating resin layer, said secondinsulating layer having grooves therein receiving said conductive leads,and said first insulating layer having windows therethrough belowselected points of said conductive leads through which conductiveinterconnecting leads extend connecting said conductive leads toselected portions of said conductive pattern layer.

7. The combination according to claim 6, in which said first and secondinsulating layers have pockets therein receiving said diodes.

8. The combination according to claim 1, in which said conductivepattern layer is a composite layer comprising three layers, the firstnext to said base plate being aluminum, the second covering saidaluminum layer being of aluminum-copper alloy, and the third coveringsaid aluminum-copper alloy layer being of copper.

9. The combination according to claim 1, in which each of said displayunits includes seven diodes in a figure 8 configuration, in which aneighth diode provides a decimal point and in which a ninth diodeprovides a dash located opposite the center line of the figure eightconfiguration.

10. The method of making an alpha-numeric character display device whichincludes coating a transparent glass plate with a conductive layer,mounting said glass plate in spaced relation on a support plate, etchingsaid conductive layer to provide a conductive pattern, said conductivepattern forming separated segments outlining a seven arm figure 8configuration with said seg ments on opposite sides of the said arms,the segments forming one side of each arm being commonly connected, saidetching also includes providing a terminal for each group of commonlyconnected segments of one side of each arm and separate sub-terminalsfor the segments forming the other side of each of said arms, coatingsaid conductive pattern with a first insulating resin layer, etchingpockets in said first insulating layer for receiving diodes to form thearms of the figure 8 configuration, inserting diodes in said pocketswith their pn junction planes perpendicular to said glass plate,covering said first insulating layer with a second insulating layer,forming seven longitudinal grooves in the outer surface of said secondinsulating layer, providing windows through said first and secondinsulating layers connecting respectively seven longitudinal grooveswith said sub-terminals, and filling said grooves and said windows witha conductive material.

11. The method of mounting electronic parts on an insulating board,which comprises the steps of: forming a conductive lead pattern layer onthe insulating board corresponding to the connection terminal of theelectronic parts, setting the electronic parts in their desiredpositions on the insulating board, forming a resin layer having aconcavity around each connection point between the conductive leadpattern layer and the connection terminal of the parts, and pouring aconductive resin into the concavity so that the electronic parts and theconductive pattern layer are electrically connected.

12. The method according to claim 11, in which electronic parts arefixed by: pouring a photosensitive adhesive resin between the electronicparts and the insulating board, and exposing the photo-sensitiveadhesive resin by using the conductive lead pattern layer so that UNITEDSTATES PATENT OFFICE CERTIFICATE OF QORRECTLON Patent No. 5,8273% DatedJuly 50, 197

lnventofls) Setsuo Usul It is certified that error appears in theabove-identified patent Letters Patent are hereby corrected as shownbelow:

line 38,ehange "200!" to --50g.:200cc-.

and that said Coiuinn C u 4311116 57 change "IL -HA' to --IVA'-IVA'--.

Coll-mm line ch ange "39 to "36". Column 6, line 20, Change "14" to 15";

line 22, change "15" to "16";

' line 28 change "16" to "17".

Column line 32 change window 39" to resin layer 36--;

lin 51 change "39" to "365-.

Column 7, line 5 change "68" to Signed and Scaled this twenty-third a OfDecember 1 9 75 [SEAL] Arrest:

RUTH- C. MfAHSON C. MARSHALL DANN Arresting Officer CommissionerofPatents and Trademarks

1. In an alpha-numeric character display device composed of a pluralityof similar display units, each having a plurality of light emittingdiodes similarly arranged in a display array to be selectively energizedto depict different desired characters, the combination comprising atransparent glass base plate, a conductive layer pattern formed on saidbase plate having individual paths for one side of each diode of eachdisplay unit and having a common path for the other side of all diodesin one display unit but separate paths for different units, a pluralityof parallel disposed conductive leads corresponding in number to thetotal number of diodes in a single display unit running lengthwise ofsaid device in a plane above said conductive pattern, the first side ofall similarly located diodes of the different display units beingelectrically connected together through said conductive leads and saidconductive layer pattern, there being one conductive lead for each groupof similarly located diodes, and a terminal for each conductive lead anda terminal for each common path to said other side of the diodes of eachdisplay unit.
 2. An alpha-numeric character display unit comprising atransparent non-conductive plate, a conductive layer on one surface ofsaid plate shaped in a predetermined pattern, said pattern includingseparated segment portions spaced to form a seven arm figure 8configuration with pairs of said segment portions on opposite sides ofsaid arm locations, and separate segment portions forming the other sideof the arm locations, the segment portions forming one side of each armlocation being commonly connected, a terminal for said commonlyconnected segment portions, separate sub-terminals for each said othersegment portion, separate lead conductors for the segments forming theother side of each arm location respectively, first insulating layermeans covering said conductive layer except for pockets opposite saidarm locations, a light emitting diode in each pocket having anode andcathode electrodes having their respective pn junctions in planesperpendicular to said plate, said electrodes being in abuttingelectrical contact respectively with segment portions on each side ofsaid arm locations, a second insulating layer covering said firstinsulating layer and said diodes, said second insulating Layer havinggrooves in the upper surface thereof in which said lead conductors aredisposed, said insulating layers having windows therethrough below eachlead conductor opposite a different sub-terminal respectively, aconductive material filling each of said windows and connecting each ofsaid lead conductors with its associated sub-terminal, and a thirdinsulating layer covering said second insulating layer.
 3. Analpha-numeric character display unit, comprising a transparentnon-conductive plate, a conductive layer on one surface of said plateshaped in a predetermined pattern, said pattern including separatedsegment portions spaced to form a seven arm figure 8 configuration withpairs of said segment portions on opposite sides of said arm locations,the separate segment portions forming the other side of the armlocations, the segment portions forming one side of each arm locationbeing commonly connected, a terminal for said commonly connected segmentportions, separate sub-terminals for each said segment portion, separatelead conductors for the segments forming the other side of each armlocation respectively, first insulating layer means covering saidconductive layer except for pockets opposite said arm location, a lightemitting diode in each pocket having anode and cathode electrodes havingtheir respective pn junctions in planes perpendicular to said plate,said electrodes being in abutting electrical contact respectively withsegment portions on each side of said arm locations, said leadconductors being disposed on the opposite surface of said firstinsulating layer means from said conductive layer, said first insulatinglayer means having a window therethrough below each lead conductoropposite a different sub-terminal respectively, a conductive materialfilling each of said windows and connecting each of said lead conductorswith its associated sub-terminal, and a second insulating layer coveringsaid first insulating layer.
 4. An alpha-numeric character display unitaccording to claim 2, in which said second insulating layer is atransparent resin, and a portion of the resin forming said second layerlies between each diode junction and said transparent nonconductiveplate.
 5. A combination according to claim 1, in which a transparentresin layer lies between each diode and said transparent glass plate,said resin layer forming a contiguous layer with said conductive layerpattern below each of said diodes.
 6. A combination according to claim1, in which an insulating resin layer is formed on said conductivepattern layer and a second insulating resin layer is formed on saidfirst insulating resin layer, said second insulating layer havinggrooves therein receiving said conductive leads, and said firstinsulating layer having windows therethrough below selected points ofsaid conductive leads through which conductive interconnecting leadsextend connecting said conductive leads to selected portions of saidconductive pattern layer.
 7. The combination according to claim 6, inwhich said first and second insulating layers have pockets thereinreceiving said diodes.
 8. The combination according to claim 1, in whichsaid conductive pattern layer is a composite layer comprising threelayers, the first next to said base plate being aluminum, the secondcovering said aluminum layer being of aluminum-copper alloy, and thethird covering said aluminum-copper alloy layer being of copper.
 9. Thecombination according to claim 1, in which each of said display unitsincludes seven diodes in a figure 8 configuration, in which an eighthdiode provides a decimal point and in which a ninth diode provides adash located opposite the center line of the figure eight configuration.10. The method of making an alpha-numeric character display device whichincludes coating a transparent glass plate with a conductive layer,mounting said glass plate in spaced relation on a support plate, etchingsaid conductive layer to provide a conductive pattern, said cOnductivepattern forming separated segments outlining a seven arm figure 8configuration with said segments on opposite sides of the said arms, thesegments forming one side of each arm being commonly connected, saidetching also includes providing a terminal for each group of commonlyconnected segments of one side of each arm and separate sub-terminalsfor the segments forming the other side of each of said arms, coatingsaid conductive pattern with a first insulating resin layer, etchingpockets in said first insulating layer for receiving diodes to form thearms of the figure 8 configuration, inserting diodes in said pocketswith their pn junction planes perpendicular to said glass plate,covering said first insulating layer with a second insulating layer,forming seven longitudinal grooves in the outer surface of said secondinsulating layer, providing windows through said first and secondinsulating layers connecting respectively seven longitudinal grooveswith said sub-terminals, and filling said grooves and said windows witha conductive material.
 11. The method of mounting electronic parts on aninsulating board, which comprises the steps of: forming a conductivelead pattern layer on the insulating board corresponding to theconnection terminal of the electronic parts, setting the electronicparts in their desired positions on the insulating board, forming aresin layer having a concavity around each connection point between theconductive lead pattern layer and the connection terminal of the parts,and pouring a conductive resin into the concavity so that the electronicparts and the conductive pattern layer are electrically connected. 12.The method according to claim 11, in which electronic parts are fixedby: pouring a photosensitive adhesive resin between the electronic partsand the insulating board, and exposing the photo-sensitive adhesiveresin by using the conductive lead pattern layer so that the parts arefixed thereby.